Since we kind of stumbled onto a believe-or-not-believe theme for the day, here’s one that leaves me not knowing what to believe.

Who’s to blame for Mark Teixeira’s latest setback?

When he ran in the outfield on Thursday and said he wanted to play on Friday, I read plenty of messages in all sorts of formats saying Joe Girardi was being overly cautious again. It’s a familiar gripe about Girardi, in his rules about reliever workload and his tendency to give veterans regular turns at designated hitter even if it means putting a lesser player in the lineup.

Teixeira said he could play. Why not let him play?

A day later, Teixeira got hurt playing at less than 100 percent. Why let him play?

“I had to try it out,” Teixeira said. “If you wait until you’re 100 percent, you wait months. You have to see if you can play. … …I pulled my quad in 2007, missed a month. It was tight for another year and a half. It was tight for a long time. Am I not going to play for that long? I thought it was just tight (Saturday) night but obviously it was still healing. I couldn’t play through it.”

Teixeira said his calf was tight throughout Saturday’s game, but it gave out when he tried to beat out that double play ball in the ninth.

“I do believe he was ready to go,” Girardi said. “But I believe he just got in a crazy play.”

If not for that one play when he really had to test the calf, Teixeira might have gotten through Saturday’s game and felt good enough play through it on Sunday. Give him a day off today, and maybe he’d be a little better tomorrow. And a little better the day after that.

So what do you believe? Is Girardi too cautious? Too reckless? Are the DH days what’s allowed Derek Jeter and Alex Rodriguez to avoid wear-and-tear injuries this season? Are the Yankees pushing the envelope using Dave Robertson and Rafael Soriano for four or five outs at a time?